This application claims the priority of German Patent Document 100 12 975.7, filed in Germany, Mar. 16, 2000, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a heating or air-conditioning system for ventilating a passenger cell of a vehicle. Preferred embodiments of he invention relate to a heating or air-conditioning system for ventilating a passenger cell of a vehicle, having an air-conditioning box, in which a heat exchanger, through which air can flow, is accommodated and at least one air-mixing chamber is formed, the air-mixing chamber having an inflow opening for hot air flowing through the heat exchanger and an inflow opening for cold air flowing around the heat exchanger, and also having at least two outflow openings, in particular for the connection of ventilation ducts leading into the passenger cell, with said system also having an air-mixing device controlling opening cross sections of the inflow openings.
In a known heating or air-conditioning system of this type (German Patent Document DE 198 16 332 C1), for the purpose of keeping the air-conditioned zones in the passenger cell, for example, the central plane and the footwell, which are ventilated by the two outflow openings, at different temperatures, the air-mixing device has two separate closing members for the hot-air and cold-air inflow openings in the air-mixing space. The closing member for the cold-air inflow opening consists of two pivoting flaps which are arranged vertically one above the other, jointly cover the cold-air inflow opening and are offset with respect to each other by a fixed angle of rotation. This offset is undertaken in such a manner that when the closing member is opened, the upper air flap always opens up a larger opening cross section of the cold-air inflow opening than the lower air flap, with the result that temperature stratification of the mixed air arises in the mixed-air chamber and a ventilation duct, which is connected to the lower outlet opening, conducts hot air kept at a higher temperature than a ventilation duct which is connected to the upper outflow opening.
The reason for this temperature stratification in the air-mixing chamber is the finding that the occupant perceives a hot-air flow in the head region to be unpleasant, but perceives it to be pleasant in the foot region and so it is endeavored to keep the hot-air flow in the head region at a lower temperature level than the hot-air flow flowing into the footwell.
An object of the invention is to design a heating or air-conditioning system of the type mentioned at the beginning in such a manner that with little structural outlay ventilation, which is pleasant for the occupant, of the passenger cell, in particular of the rear area of the passenger cell, is ensured in all operating states of the system.
The invention achieves this object by providing a heating or air-conditioning system for ventilating a passenger cell of a vehicle, having an air-conditioning box, in which a heat exchanger, through which air can flow, is accommodated and at least one air-mixing chamber is formed, said air-mixing chamber having an inflow opening for hot air flowing through the heat exchanger and an inflow opening for cold air flowing around the heat exchanger, and also having at least two outflow openings, in particular for the connection of ventilation ducts leading into the passenger cell, with said system also having an air-mixing device controlling opening cross sections of the inflow openings,
wherein one outflow opening has arranged on it a restricting element which is intended for restricting the opening cross section and is actuated by the air-mixing device in such a manner that the opening cross section of the outflow opening is restricted to the maximum when the hot-air inflow opening is opened up to the maximum, and is completely opened up when the cold-air inflow opening is opened up to the maximum.
The heating or air-conditioning system according to the invention has the advantage that the restrictable outflow opening reduces the quantity of hot air flowing into one ventilation duct, which is preferably used for ventilating the central plane in the rear area, in the heating mode and maximizes it in the cooling mode. Therefore, in the heating mode a great quantity of air which is kept at a uniform temperature flows into the footwell and only a reduced quantity flows into the central plane. In the heating mode, this results in a pleasant climate in the rear area without hot air unpleasantly streaming into the central plane and reaching as far as the head region. During cooling, in contrast, the cold air is distributed uniformly to both ventilation ducts and therefore uniformly to both ventilation regions. This is also advantageous, since cooling air in the central planexe2x80x94in contrast to hot airxe2x80x94is perceived to be pleasant. The air distribution which is described is achieved without a great outlay and without an additional actuating drive as a result of the air-mixing device actuating the restricting element. The ventilation setting cannot be incorrectly operated.
Advantageous embodiments of the heating or air-conditioning system according to the invention together with expedient developments and refinements of the invention are specified herein and in the claims.
According to one advantageous feature of preferred embodiments of the invention, the air-mixing device has two separate closing members, one of which controls the opening cross section of the hot-air inflow opening and one the opening cross section of the cold-air inflow opening, the restricting element being forcibly coupled to one of the two closing members. This forcible coupling saves on a separate drive for the restricting element andxe2x80x94since there is no intervention option for the occupantxe2x80x94makes incorrect operation impossible.
According to another advantageous feature of preferred embodiments of the invention, the restricting element is designed as a pivoting slide which can be pivoted about a rotational spindle, which runs parallel to the perpendicular of the outflow opening, in a plane parallel to the outflow opening. Rotation of the pivoting slide causes the outflow opening to be covered to a greater or lesser extent, it being possible for the maximum coverage to be set in a very simple manner.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.